1. Field of the Invention
The present invention relates to a vacuum processing apparatus and more particularly, an improvement of the load lock chamber used in the LCD substrate processing apparatus.
2. Description of the Related Art
Vacuum processing apparatuses provided with plural process chambers, in which predetermined processes such as etching and ashing are applied to semiconductor wafers and liquid crystal device (LCD) substrates, have been used in the course of manufacturing semiconductor devices and LCDs.
In the case of these vacuum processing apparatuses, three vacuum process chambers, for example, are arranged around an auxiliary vacuum chamber (or load lock chamber) in which a substrate carrier mechanism, such as a carrier arm, is arranged. LCD substrates, for example, which are to be processed, are carried into and out of the process; chambers by the carrier arm and predetermined processes are applied to them in these process chambers.
In the case of the vacuum processing apparatus in which LCD substrates are processed, it is an important technical problem as to how many sheets of substrates can be processed over a certain period of time or how the throughput of the apparatus can be enhanced. In addition, LCDs have been used as display devices for large-sized computers and televisions and they therefore become larger in size for this purpose. As they become larger in size, however, the productivity of LCD substrates is reduced and the manufacturing cost per LCD substrate is increased to a greater extent.
One of the causes of a reduction in productivity as described above resides in the fact that contamination is caused by contamination such as particles located in the apparatus. In addition, the shifting of LCD substrates from their predetermined positions is another cause of contamination. When they are shifted from their predetermined positions, they are dropped and damaged while they are being carried, or uniform performance of the process applied to them is degraded. Productivity is thus reduced. Particularly when they are larger in size, they are more likely to be moved by the vacuum-generating exhaust of the load lock chamber, for example. They are thus shifted from their predetermined positions.
Further, LCD substrates are of various sizes and there are various processes applied to these LCD substrates. The vacuum processing apparatus, therefore, must be made more flexible to meet these various sizes and processes.